A: Coordination number of `Fe^(2+)` in ferrocene is 10.
R: Ferrocene is`pi` bonded complex 

Options

A. If both Assertion & Reason are true and the reason is the correct explanation of the assertion, then mark (1)
B. If both Assertion & Reason are true but the reason is not the correct explanation of the assertion, then mark (2).
C. ) If Assertion is true statement but Reason is false, then mark (3).
D. If both Assertion and Reason are false statements, then mark (4)

Answer

To solve the question regarding the coordination number of `Fe^(2+)` in ferrocene and whether it is a pi-bonded complex, we can break down the explanation into clear steps:

### Step-by-Step Solution:

1. **Understanding Ferrocene Structure**:
- Ferrocene is an organometallic compound consisting of an iron (Fe) atom sandwiched between two cyclopentadienyl (Cp) anions. Each cyclopentadienyl ring is a five-membered carbon ring with a negative charge.

2. **Coordination Number Definition**:
- The coordination number of a metal in a coordination complex refers to the number of ligand donor atoms that are bonded to the central metal atom. In ferrocene, the coordination number is determined by the number of points of attachment from the ligands to the metal.

3. **Analyzing Ligand Attachment**:
- In ferrocene, each cyclopentadienyl ligand (Cp) donates electrons to the iron atom. Since there are two Cp ligands, and each ligand has five carbon atoms, the total number of points of attachment to the iron is 10 (5 from the top Cp and 5 from the bottom Cp).

4. **Confirming Coordination Number**:
- Therefore, the coordination number of `Fe^(2+)` in ferrocene is indeed 10, as it is surrounded by 10 carbon atoms from the two cyclopentadienyl ligands.

5. **Understanding Pi Bonding**:
- Ferrocene is classified as a pi-bonded complex because the bonding between the iron and the cyclopentadienyl ligands involves pi-electron donation. The cyclopentadienyl ligands do not form traditional sigma bonds with the iron; instead, they interact through their pi systems.

6. **Conclusion**:
- Both statements in the question are correct: the coordination number of `Fe^(2+)` in ferrocene is 10, and ferrocene is indeed a pi-bonded complex.

### Final Answer:
- A: Coordination number of `Fe^(2+)` in ferrocene is 10.
- R: Ferrocene is a pi-bonded complex.
- Both statements are true.